The air elimination and oil exchange of hydraulic brake or hydraulic clutch system are important operations in the maintenance of an automobile, which have necessitated two or three persons if such operations are to be conducted manually. For example, the air elimination or oil exchange for a hydraulic brake system has required a person for actuating the push rod of the master cylinder by pressing the brake pedal, an another person for replenishing oil to a reserve tank attached to the master cylinder, and a still another person for operating air nipple provided on each wheel cylinder. In order to enable a single operator to perform such air elimination or oil exchange of the hydraulic brake system or hydraulic clutch system, therefore, there has been proposed a servicing machine comprising an oil replenisher mounted on the reserve tank of the hydraulic system for automatic oil replenishing to a given level, said reserve tank being connected to a master cylinder operated by an operator, check valves mounted on the air nipples provided on the oil cylinders connected to said master cylinder, said check valves allowing the oil to flow only in one direction thereby releasing the oil to outside while said air nipples being maintained open, and a receive tank connected with said check valves to receive the oil exhausted from the oil cylinder through said check valves. Such machine has however encountered difficulties that the oil replenisher is difficult to mount on the reserve tank or the oil control valve of said oil replenisher is difficult to manipulate even if the mounting is possible due to a fact that the reserve tanks of hydraulic brake or hydraulic clutch systems in an automobile are usually located in a place highly crowded with other devices.